The present invention relates to optical storage devices, and more particularly, to a method and apparatus for decoding encoded data around a discontinued area on an optical storage medium.
Data can be repeatedly recorded on an optical storage medium such as a DVD+RW disc, a DVD-RW disc, or a Blu-ray disc. This means that multiple sets of data can be recorded on the optical storage medium at various times. In an ideal case, a boundary of a second set of data recorded after a first set of data is right next to the first set of data so the adjacent sets of data appear to be continuous. In other words, there is no overlap or blank region around the linking area of the adjacent sets of data.
In reality, however, there usually exists an overlap or blank region around the linking area of the adjacent sets of data due to certain factors such as inaccuracy of a clock signal or occurrence of an error during addressing. In the worst case, the overlap region introduces a decoding error of recorded data corresponding to a whole error correction unit, e.g. an error correction code (ECC) block (for DVD+RW discs or DVD-RW discs) or a cluster (for Blu-ray discs), if too many portions within the error correction unit are shifted due to the overlap region.